Easy way to model spiral engraving (knurling) that is usually used on metal for better grip?
Subdivide the area you want to engrave to have enough supporting geometry:


Subdivide it one more time - W > Subdivide:


Unsubdivide - Ctrl+E > Unsubdivide, choose Iterations: 1 in operator properties:


Select single face and select similar - Shift+G > Area:


Poke faces Alt+P and switch to vert select:


Select these 2 vertices:


Select similar - Shift+G > Amount of connecting edges:


Scale these in with Alt+S:


Mark sharp smoothing on the whole area.